Latest post Sun, Sep 8 2019 7:22 PM by Kyler. 8 replies.
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  • Mon, Sep 2 2019 12:06 AM

    • Kyler
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    • Joined on Wed, Feb 26 2014
    • Boudreau
    • Posts 33
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    Major audio drift in one hour video

    Hey everyone, I've got footage shot on a Canon HD camera along with 48K audio from a mixing board. When I lay in the audio and export from Avid (exporting as ProRes) the audio is in sync at the beginning, and then at least 5-67 frames off by the end. My project is a 29.97 1080p project and I'm AMA linking to the video and audio filies.

    Version of Avid is 2019.7.0.52735.0

    On the timeline, the audio is two mono tracks. No FX applied. I haven't done a mixdown.

    Thanks for any ideas!

    p, li { white-space: pre-wrap; }

    Macbook Pro Retina, 2.7GHz Quadcore, 16GB RAM. [view my complete system specs]

     

    kyler boudreau | theatereleven.com

     

     

  • Mon, Sep 2 2019 6:31 AM In reply to

    • Martin Fox
    • Top 500 Contributor
    • Joined on Fri, Mar 14 2014
    • Sydney Australia
    • Posts 250
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    Re: Major audio drift in one hour video

    Is the end of the program in sync in the timeline?

    With my gear zoom and fostex sound recorders, Sony A7s camera the synch drift is about 3 frames over an hour (cheap internal clocks)

    my solution is to use time compression audio effect (no pitch shift)  to make the sound fit the picture, or edit the sound to make it fit, then export.

    Gerald Undone on youtube has a demo for premier to take you through the steps. 

    iMac Retina27 late 2017 4.5Gz i7 40GB AMD 8GB with Sata Raid OS 10.13.4 MC 2018.3 BMD mini monitor with Eizo monitor [view my complete system specs]
  • Mon, Sep 2 2019 6:35 PM In reply to

    • hbrock
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    • Moderator: Avid Xpress Pro Mac
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    Re: Major audio drift in one hour video

    You might have inadvertently changed the playback rate of the 48 KHz audio.  Check the audio import settings and see if Sample rate conversion was checked as well as Do not convert sources with pull up or pull down.  Whatever they were set to, try the opposite and see if things change.

    MacPro, MacBook Pro and a Cube (masquerading as a kleenex dispenser). [view my complete system specs]

    Must think of something clever to go here...

  • Wed, Sep 4 2019 3:10 AM In reply to

    • Kyler
    • Not Ranked
    • Joined on Wed, Feb 26 2014
    • Boudreau
    • Posts 33
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    Re: Major audio drift in one hour video

    Thanks! I've tried changing the audio settings and it didn't change anything. Really weird... This came from a mix board that I guess might have an issue. The odd thing is I've received audio from this board a few other times while shooting on the same camera, and I think that stuff was fine.

    I looked at the audio pitch tool, but it's not clear on usage. I did manage to compress to make it fit, but the sound of the audio screws up. I tried different settings and just couldn't get an acceptable sound. The sound we be good and then go to a weird muffled feel.

    Guess I'm scrapping this unless there's another way to force this video and audio to be in sync.

    What's the best way to shoot and avoid this? I've cut multiple feature films in Avid without issues. But this hour long talk stuff is killing me.

    Macbook Pro Retina, 2.7GHz Quadcore, 16GB RAM. [view my complete system specs]

     

    kyler boudreau | theatereleven.com

     

     

  • Wed, Sep 4 2019 5:00 AM In reply to

    Re: Major audio drift in one hour video

    Kyler:
    I'm AMA linking to the video and audio filies

    If you transcode them does the problem persist?

    Media Composer 2019.12 w/Symphony/SS/PF options, HP Envy 17t-j100 Quad Edition laptop, Windows 10 Pro, Intel Core i7 2.4GHz, 16 GB RAM, nVidia GeForce... [view my complete system specs]

    "There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who only consider the price are this man's lawful prey."  - John Ruskin (1819-1900)

     

    Carl Amoscato | Freelance Film & Video Editor | London, UK

  • Wed, Sep 4 2019 1:26 PM In reply to

    • Kyler
    • Not Ranked
    • Joined on Wed, Feb 26 2014
    • Boudreau
    • Posts 33
    • Points 385

    Re: Major audio drift in one hour video

    Good idea. I was wondering if the problem would go away if I did the old school import and let Avid convert the footage to MXF files. I can try the transcode and see what happens. Thank you!

    Macbook Pro Retina, 2.7GHz Quadcore, 16GB RAM. [view my complete system specs]

     

    kyler boudreau | theatereleven.com

     

     

  • Sun, Sep 8 2019 5:27 PM In reply to

    • Kyler
    • Not Ranked
    • Joined on Wed, Feb 26 2014
    • Boudreau
    • Posts 33
    • Points 385

    Re: Major audio drift in one hour video

    Hey everyone, so I'm the idiot: 

    Zero audio drift. The camera spits out chunks of video during the hour long recording. I throw them back to back into the timeline. Somehow, one was ten frames off. Have no idea how that happened since I don't mark ins and outs, but that was the issue. 

    Thanks for the help. I'll go be a brain doner now.

    Macbook Pro Retina, 2.7GHz Quadcore, 16GB RAM. [view my complete system specs]

     

    kyler boudreau | theatereleven.com

     

     

  • Sun, Sep 8 2019 5:36 PM In reply to

    Re: Major audio drift in one hour video

    Haha, thanks for coming back and telling us what it was. Might save someone else making a similar mistake.

    Media Composer 2019.12 w/Symphony/SS/PF options, HP Envy 17t-j100 Quad Edition laptop, Windows 10 Pro, Intel Core i7 2.4GHz, 16 GB RAM, nVidia GeForce... [view my complete system specs]

    "There is hardly anything in the world that some man cannot make a little worse and sell a little cheaper, and the people who only consider the price are this man's lawful prey."  - John Ruskin (1819-1900)

     

    Carl Amoscato | Freelance Film & Video Editor | London, UK

  • Sun, Sep 8 2019 7:22 PM In reply to

    • Kyler
    • Not Ranked
    • Joined on Wed, Feb 26 2014
    • Boudreau
    • Posts 33
    • Points 385

    Re: Major audio drift in one hour video

     

    Yeah, basically don't assume it's always something complicated and mysterious. If your long form audio is delivered in separate files, watch all of those and ensure no frames are missing! Much faster. [:'(]

    Macbook Pro Retina, 2.7GHz Quadcore, 16GB RAM. [view my complete system specs]

     

    kyler boudreau | theatereleven.com

     

     

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